Goodwill and Intangible Assets, Net (Details 1) (USD $)	3 Months Ended		9 Months Ended
	Dec. 30, 2012	Jan. 01, 2012	Dec. 30, 2012	Jan. 01, 2012	Apr. 01, 2012
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Assets, Amortization Expense	$ 4,700,000	$ 4,000,000	$ 15,100,000	$ 12,100,000
Gross assets	384,907,000		384,907,000		356,308,000
Accumulated amortization	(330,903,000)		(330,903,000)		(315,760,000)
Net assets	54,004,000		54,004,000		40,548,000
Estimated amortization expense [Abstract]
2013 (Remaining 6 months)	4,673,000
2014	17,184,000
2015	13,460,000
2016	8,448,000
2017 and thereafter	7,806,000
Total	51,571,000
Existing Technology [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross assets	241,933,000		241,933,000		223,733,000
Accumulated amortization	(200,191,000)		(200,191,000)		(192,105,000)
Net assets	41,742,000		41,742,000		31,628,000
Trademarks [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross assets	4,411,000		4,411,000		2,911,000
Accumulated amortization	(1,789,000)		(1,789,000)		(1,144,000)
Net assets	2,622,000		2,622,000		1,767,000
Customer Relationships [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross assets	131,930,000		131,930,000		127,231,000
Accumulated amortization	(127,223,000)		(127,223,000)		(122,511,000)
Net assets	4,707,000		4,707,000		4,720,000
Other Intangible Assets [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross assets	4,200,000		4,200,000
Accumulated amortization	(1,700,000)		(1,700,000)
Net assets	2,500,000		2,500,000
Subtotal [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross assets	382,474,000		382,474,000		353,875,000
Accumulated amortization	(330,903,000)		(330,903,000)		(315,760,000)
Net assets	51,571,000		51,571,000		38,115,000
In Process Research and Development [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Gross assets	2,433,000		2,433,000		2,433,000
Accumulated amortization	0		0		0
Net assets	$ 2,433,000		$ 2,433,000		$ 2,433,000
Minimum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	12 months
Maximum [Member]
Acquired Finite-Lived Intangible Assets [Line Items]
Finite-Lived Intangible Asset, Useful Life	7 years